"that is done or which involves sitting down," 1836 in reference to meals; 1936 in reference to strikes where the workplace is occupied; from the verbal phrase meaning "take a seat, seat oneself" (c. 1200), from sit (v.) + down (adv.). Sit down (v.) meaning "put up (with)" is attested from c. 1600, hence to (not) take something sitting down. As a noun, sit-down "act of sitting down" is from 1861, especially a sitting down together for friendly or social intercourse.
also shakedown, 1730, "impromptu bed made upon loose straw," from the verbal phrase; see shake (v.) + down (adv.). The verbal phrase shake down is attested from late 14c. as "shake into place, compact by shaking" also "cause to totter and fall." The meaning "forced contribution" (1902) is from the verbal phrase in a slang sense of "blackmail, extort" (1872). Meaning "a thorough search" is from 1914; perhaps from the notion of measuring corn; the verbal sense of "to frisk or search" is by 1915 in police reporting.
"insult, snub," 1962, from verbal phrase put down "to snub," attested from c. 1400 in this sense, earlier (c. 1300) "to lower, let down," also (mid-14c.) "to throw down, reject;" see put (v.) + down (adv.). To put (something) down "end by force or authority" (a rebellion, etc.) is from mid-14c. Compare set-down "a rebuff, a scolding" (1780).